Many industrial processes require subjecting material to elevated temperatures on the order of 1000° F. to 3000° F. Examples of such processes include melting aluminum and other metals, maintaining molten metal in the molten state, melting glassmaking materials, and maintaining glass in the molten state. To generate the required elevated temperature, processes requiring such elevated temperatures often combust carbonaceous fuel, in one or more burners each of which produces a flame situated close enough to the material that the heat of combustion establishes the desired elevated temperature in the material.
Typically the one or more burners used for this purpose each generate a flame that extends outward from the burner in a fixed position, such as extending from a side wall of a furnace across and over the top of a portion of the material to be heated. Such arrangements are not necessarily as efficient as possible, because the temperatures at various points around the outer surface of the flame and along the length of the flame are not uniform so that there is a region of the flame that has the highest temperature and heat flux to the material. This lack of uniformity means that the position of the burner relative to the material being heated, and the conditions under which the burner is operated, must be set so that the highest temperatures and heat flux generated by the burner are not so high as to produce unwanted results such as “hot spots” in the material or the enclosure in which the combustion is being carried out, excessive oxidation of the material, or damage to the enclosure. However, doing so often requires accepting temperatures at other points around the flame that are not as high as could be tolerated, and thereby requires accepting less than optimum performance of the burner.
This lack of efficiency has heretofore been considered acceptable for a number of reasons including the absence of a useful method and apparatus that can provide greater uniformity of temperature. The present invention provides apparatus and methods of use that overcome this lack of efficiency.